The difference between these two zones is approximately five hours. Eastern Standard Time is five hours behind Greenwich Mean Time. The former zone is Coordinated Universal Time (UTC) -5:00, while the latter is UTC 00:00. Above this text, you?ll find a chart with each hour of the day converted between the two zones. At the top of the page you?ll find a clock that is live each hour showcasing the difference between the two zones down to the second. Let?s check out an example: If it is 6:25 PM in the GMT zone, then it 1:25 PM in the EST zone. Simply subtract five hours from the time.Now, if Daylight Saving Time is in effect, there is a small difference. In this case, since the people in the Eastern zone move their clocks forward an hour to Eastern Daylight Time, the difference becomes four hours, not five. So, just remember to subtract four hours when converting during the summer months.The Greenwich Time Zone This time zone represents the birthplace of the concept. The countries which observe this time are as follows: Burkina FasoCote d?Ivoire Britain (United Kingdom) GuernseyGhanaGreenlandGambiaGuineaGuinea-BissauIreland Isle of ManIcelandJerseyLiberiaMaliMauritaniaSt. HelenaSierra LeoneSenegalSao TomePrincipe TogoThis time zone is the mean solar time located at the Royal Observatory in Greenwich, London. Originally it was the standard for civil time, but it has since been replaced by Coordinated Universal Time. Earth spins at an uneven rate because of its elliptical orbit and the tilt of its axis. As a result of these facts, ?noon? is very rarely the time that the sun is at its highest point. As a result, Noon in this time zone is the approximate time of the event on an average. This is where the ?mean? comes from in the zone?s name. The Eastern Time ZoneThe EST zone is used as kind of the ?official? time for the United States. This is because the zone includes the nation?s capital of Washington D.C and the largest city which is New York. National news outlets will often report events using this time zone and schedule broadcasts using this standard, even if the actual event is in another zone.Daytime talk shows, evening news, talent & award shows, and other events are broadcasted live in this time zone and advertised using this zone in other areas. Beyond the usage of this time in the United States, parts of Canada, and the Caribbean, it is also used by Panama in Central America year-round. , The difference between these two zones is approximately five hours. Eastern Standard Time is five hours behind Greenwich Mean Time. The former zone is Coordinated Universal Time (UTC) -5:00, while the latter is UTC 00:00., Convert Eastern Standard Time (EST) now to Greenwich Mean Time (GMT) now with this free and simple time zone converter and time zone table!.